you HAVE to run vette aluminum head guide plates from GM with those rockers. the intake valve is off center from a regular SBC head and all aftermarket guide plates will cause intake valve side load. Now a stock LT1 has valve reliefs in the pistons. you can run high 230 duration with about 560 lift with out too much PTV. Now intake centerline and LSA also come into play But on the lower side say 228/230 540/560 lift cam you will be fine. SO your basically in a boat to use a baby cam Just to be able to run those rocker. if it were me and io already had them and i wasnt going to pull a head to check PTV. id run them on a stock cam stock LOW MILAGE? springs. or run the cc304 cam and run 941 springs and retainers. CC305 cam Might work But again i KNOW these 2 combos will work without any head modification to fit a longer/heavier spring in the pockets. or having any PTV issues. hope it helps.
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1998 Firebird:buncha parts thats used to make it go fast..... not so much anymore. 
BAAAAAA!!!!!!
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